package com.github.kezhenxu94.playground.leetcode;

/**
 * 190. Reverse Bits Reverse bits of a given 32 bits unsigned integer.
 * 
 * For example, given input 43261596 (represented in binary as
 * 00000010100101000001111010011100), return 964176192 (represented in binary as
 * 00111001011110000010100101000000).
 * 
 * Follow up: If this function is called many times, how would you optimize it?
 * 
 * TODO Optimize
 * 
 * @author ke.zhen.xu
 *
 */
public class Solution190ReverseBits {

	// you need treat n as an unsigned value
	public int reverseBits(int n) {
		long unsigned = 0x00000000FFFFFFFFL & n;
		int result = 0;
		for (int i = 0; i < 32; i++) {
			result <<= 1;
			result += unsigned % 2;
			unsigned >>= 1;
		}
		return result;
	}
}
